This invention relates generally to information distribution and processing, and more particularly to distributing information using a broadcast channel and a bi-directional communication channel.
Recent advances in modem and computer technology allow large amount of digital data to be transmitted electronically. A number of information providers (such as newspaper and magazine publishers) and on-line information distributors (such as America Online, Dialog and Nexis) have formed partnerships to deliver newspaper and other information on-line. In this system, a subscriber uses a computer and a modem to connect (e.g., through a regular phone line) to the computer of an on-line information distributor. The subscriber can retrieve information, including newspaper articles, stored in the computer of the information distributor.
On-line delivery of newspaper has many advantages. For example, the information can be updated throughout the day while the printed version is printed only once or twice a day. Further, it is possible to do text-based searches on the information. However, it is found that on-line deliver of newspaper and other information is slow. For example, a subscriber has to wait many seconds for a newspaper article to be delivered. The quality of the electronic newspaper is low. For example, in order to reduce storage and communication requirements, graphic images appeared in the printed version are not universally supplied in the on-line version of newspaper. One of the reasons for such poor performance is the limited bandwidth of communication channels used by on-line information distributors. Another reason is that information is centrally processed by the computer at the site of the information distributor, with the result that each subscriber only gets a small slice of the time of the computer.
Another way to communication information on-line is through the Internet, which is a worldwide interconnection of millions of computers, from low end personal computers to high-end mainframes. An important development in the Internet is the World Wide Web (the xe2x80x9cWebxe2x80x9d). The Web is a wide-area hypermedia information delivery and retrieval system aimed to give universal access to a large universe of documents. When the Web was first developed around 1989, it was known to and used by the academic/research community only as a means for fast disseminating of information. There was no easily available tool which allows a technically untrained person to access the Web. An important development is the release of a Web xe2x80x9cbrowserxe2x80x9d around 1993. It has a simple but powerful graphic interface. The browser allows a user to retrieve web documents and navigate the Web using simple commands and popular tools such as point-and-click. Because the user does not have to be technically trained and the browser is easy to use, it has the potential of opening up the Internet to the masses.
A document designed to be accessed and read over the web is called a web page. Each web page must have an address in a recognized formatxe2x80x94the URL, or Uniform Resource Locatorxe2x80x94that enables computers all over the world to access it. Each web page has an unique URL. A web page typically contains both text and images. It is also possible to include audio and movie data.
The Web faces the same problem as the regular on-line delivery of information. This is because most people use the above described modem to access the Internet. Thus, the data transfer rate of the Web is also limited. Because multimedia data (comprising a combination of text, graphic, video and/or audio) has a large data size, even when compressed, it could take a long time to retrieve a document from the Web. Further, it is difficult to prevent unauthorized persons from access a web page because more than 20 million people in the world has access to the Internet.
Consequently, there is a need to have an improved system for distributing information electronically.
The present invention uses two channels to deliver digital information: a broadcast channel and a bi-directional channel. The broadcast channel is used to deliver the bulb of the digital information to subscribers. The amount of information delivered is preferably sufficient to satisfy the needs of a large number of subscribers so that they do not have to obtain additional information using the bi-directional channel. The broadcast information is stored on fast storage media located at subscriber sites. As a result, search and retrieval of the broadcast information is quick. Further, the broadcast information is processed locally using a dedicated on-site processor instead of relying on the computers of the information distributors. As a result, the load on the computers of the information distributors is reduced. If the subscribers desire to receive additional information relating to the broadcast information, the bi-directional communication channel is used to transmit the request and the requested information.
The distribution costs of broadcast channels are typically much lower than that of a bi-directional communication channel. Consequently, the major portion of information is delivered using low cost distribution channels. For a large number of subscribers, the broadcast information will provide all the information they normally need. Thus, expensive bi-directional communication channels are used only occasionally.
These and other features and advantages of the present invention will be fully understood by referring to the following detailed description in conjunction with the accompanying drawings.